The present invention relates to a motorcycle having a front wheel carried by a wheel carrier.
Modern vehicles are frequently equipped with a so-called driving stability system, which on the basis of various driving state signals such as wheel speed, transverse acceleration, yaw rate, etc., continuously monitors the actual driving state, and when a critical driving state is recognized stabilizes the vehicle by active braking or fuel intervention. The driving stability systems known from the area of four-wheeled vehicles cannot be transferred to motorcycles. If the motorcycle is in an unstable lateral force state, it is usually not possible to stabilize the vehicle by a braking intervention.
The object of the invention is to provide a motorcycle having a chassis design such that in critical driving situations it is possible to stabilize the driving state by means of electronic control intervention.
The starting point of the invention is a motorcycle having a fork-like wheel carrier, on the lower end of which a front wheel is supported. The term “wheel carrier” is interpreted very broadly, and encompasses in particular telescopic forks, such as the “telelever design” developed by BMW, as well as fork-like wheel carriers produced in a one-piece design, for example in the form of a cast part, such as the “duolever front wheel suspensions” known in BMW motorcycles. Similarly as for conventional motorcycles, a handlebar is provided by means of which the wheel carrier can be steered in a steering direction, i.e., to the left or the right, during travel. The handlebar is coupled to the wheel carrier via a “transmission unit.” The transmission unit is provided for transmitting the steering forces, introduced into the handlebar by the driver, to the wheel carrier and bringing same into a corresponding steering position.
The essence of the invention lies in the fact that the wheel carrier is mounted in such a way that it is pivotable with respect to the handlebar. In this context, “pivotable” means that for a specified steering position the wheel carrier can be pivoted, at least over a certain range, in the steering direction, i.e., to the left or the right, relative to the handlebar. This additional degree of freedom allows a steering intervention to be controlled by a driving stability system, i.e., a driving stability electronics system, during travel so that a “correction” of the steering position of the wheel carrier is made, specifically, without changing the position of the handlebar specified by the driver. Therefore, it is not necessary for the handlebar to also be moved during a steering intervention.
According to one refinement of the invention, the transmission unit has an actuator by which the wheel carrier may be pivoted with respect to the handlebar during travel. The actuator may be, for example, a hydraulic cylinder, a pneumatic cylinder, an electric motor, or some other actuator which responds quickly and precisely.
Such a steering intervention may be controlled by a monitoring electronics system which during travel of the motorcycle monitors at least one, preferably multiple, driving state variables such as wheel speed, yaw rate, lateral inclination angle, pitch angle, etc., and when a critical driving state is recognized performs a steering intervention which stabilizes the driving state by controlling the actuator.
According to one refinement of the invention, the wheel carrier has a left and a right fork arm which are joined together at the region of their upper ends by a “connecting section,” or by a separate “connecting piece” which may also be referred to as an upper fork bridge. The fork arms are fixedly connected to this connecting piece, i.e., “fork bridge.” The handlebar, on the other hand, is mounted so as to be pivotable with respect to the fork bridge. From a kinematic standpoint, the actuator is situated between the handlebar and the wheel carrier, which allows the wheel carrier to pivot in relation to the handlebar. The handlebar may be supported directly on the fork bridge.
As previously mentioned, the wheel carrier may be a telescopic fork having two fork rods, each having two fork tubes which may be moved one inside the other, or may be a one-piece wheel carrier, i.e., produced in the form of a cast part.
Similarly as for the BMW motorcycles currently on the market having the known “telelever front wheel suspension” and “duolever front wheel suspension,” the wheel carrier may be suspended on the remainder of the motorcycle via one or two so-called “longitudinal control rods.” For a telelever front wheel suspension, the two lower fork tubes of the telescopic fork are joined together via a lower fork bridge, and the lower fork bridge is connected to a lower longitudinal control rod via a ball-and-socket joint centrally located in the region between the two fork rods, the rear end of the lower longitudinal control rod being pivotably supported on the frame or on the engine housing. The ends of the upper fork tubes of the two fork rods are supported in an upper fork bridge by means of ball-and-socket joints, the upper fork bridge in turn being pivotably connected to the frame of the motorcycle.
For a duolever front wheel suspension, a one-piece wheel carrier produced in the form of a cast part is provided which is suspended in an articulated manner on the frame or on the engine housing via a lower and an upper longitudinal control rod.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description when considered in conjunction with the accompanying drawings.